Cell Density And The Media Essay

(Biology Dept.). 0.1 ml of E.coli K or 0.1ml of E.coli B was added to the 10 fold dilution. Using soft agar technique, the growth media mixture with E.coli was plated and incubated.

Preliminary studies help identify Genus species of bacteria. Two different preliminary study pathways must be used since two different pathogens were found in the sample. A dilution and a quadrant streak are the ideal methods to separate pure cultures of bacteria. MacConkey Agar and CAN (MAC) is a selective media that is used for the cultivation of gram negative bacteria. (PEA) is a selective media that is used

70µL of competent E.coli are added to both test tubes; pUC18 and Lux (Alberte et al., 2012). Both test tubes are then tapped and placed back into the ice bath for 15 minutes. While waiting, another test tube is obtained, filled with 35µL of competent cells and labeled NP for no plasmid. A water bath is preheated to 37 degrees Celsius and all three labeled test tubes are inserted into the bath for five minutes (Alberte et al., 2012). Using a sterile pipet 300µL of nutrient broth are inserted into both the control and Lux test tubes and 150µL are inserted to the no plasmid test tube to increase bacterial growth. All three test tubes are then incubated at 37 degrees for 45 minutes. Six agar plates are obtained and labeled to correspond each test tube, three of the plates contain ampicillin. A pipet is used to remove 130µl from each test tube containing a plasmid and insert it into the corresponding agar plate. For this, a cell spreader is first

The best and most accurate way of identifying an unknown microorganism is by sequencing its DNA, but this is very expensive and only used in highly qualified labs. So, the identification of unknown bacteria number 63 was be done by putting the bacteria through numerous laboratory tests. Microorganisms are different among each other by their macroscopic morphology, microscopic morphology, and the unique metabolic processes they use to survive and reproduce. Identifying an unknown microorganism in the laboratory is important because knowledge is gained on the appropriate way to cultivate an organism, how to correctly read the result of a test, and learning about the different characteristics of the bacteria. All of the following tests were done using the best sterile technique and the most new turbid bacterial growth subculture.

The thioglycollate broth showed that Clostridium sporogenes, Escherichia coli, Micrococcus luteus, and Enterococcus faecalis all showed growth that was throughout the tube but there was a slight inhibition of growth at the very top of the tube. Pseudomonas aeruginosa showed growth throughout all of the tube including the very top of the tube. With the TSA + glucose plate, all the bacteria but C. sporogenes was able to grow on the plate aerobically. For the plates that were grown in anaerobic conditions, only C. sporogenes, E. coli, and E. faecalis were able to grow on the plates.

Introduction: A frequent matter in the science, medical and pharmaceutical world is identifying unknown bacteria. Throughout the past months of this class we have learned lab technique and how to do a variety of different tests on bacteria. Microbiology is not only an academic understanding of microorganisms but learning how to practically use lab procedures to properly identify and test organisms. There are several reasons one might need to identify a bacteria. It could be to find out the causative agent in a patients disease or to figure out the antibiotics that need to be administered.

As expected the higher growth was seen in the E.coli cells growing outside ampicillin environments, this is because they grow freely with only minor risk, such as contamination. Possible errors in the experiment can have included the difference in the amount of liquid broth added to the E.coli sample that contained no plasmid and that which contained a plasmid. The sample containing no plasmid received half the amount of liquid broth (150µl) as that of the other two samples (300µl). Liquid broth can have incremented the growth in the plates containing plasmid twice as much as on the rest of the plates. Another artifact which can have affected the results was the time each solution spent in both the ice and hot water bath. Uneven sharing may have also taken place within the E.coli used for each plasmid leading to different amounts of colonial growth in the different agar plates used. More accurate results would have been possible if there had been more variation in both E.coli and plasmid

All it takes is one single cell to start a pure bacterial colony. This lab allows researchers to observe isolated highly concentrated samples of bacteria, to view their traits and to isolate pure colony samples for use in future experiments. Unfortunately successful isolation was not achieved in this lab. Possible sources of error could be that the streaking was too close together resulting in an unsuccessful isolation, the loop was not flamed adequately which permitted carryover of bacteria from one sector to the next or forgetting to let the loop cool before touching the agar. To expand this lab, researchers could collect a single colony from an agar plate and grow it inside a nutrient tube to observe the oxygen nutrient requirements for that specific sample of

In this experiment, each student was randomly assigned with a different species of gram- negative bacteria. The organism that I was assigned was Unknown #16. The identity of the gram-negative bacteria was determined to be Escherichia coli. The purpose of this report is to describe the various tests that helped develop a better understanding of the unknown microorganism in terms of the physiology, morphology, motility, and antimicrobic sensitivity it is characterized with. Indole production, hydrogen sulfide, and the colony morphology on the Eosin-methylene blue (EMB) plate, were the critical results that led to the conclusion that the organism was E. coli. In the indole production test, E. coli was one of two organisms,

This experiment is about bacterial growth. We will demonstrate a bacterial growth curve using a closed system. Bacterial growth usually takes up to 12-24 hours to get an accurate result so we will be monitoring this growth between two classes. We also used different methods to determine bacterial growth as well as a few different calculations. One way of receiving data is by using a spectrophotometer where we will record the absorption at a given time to create the bacterial growth curve. We also used the plate count method after performing a serial dilution to calculate the actual cell density at different times given. By using this method we can count the population number of the same given and see the maximum cell density

The morphology for E. coli and Klebsiella in slant agar is filiform which uniform growth along the line of inoculation. The result shows E.coli and Klebsiella are not oxygen dependent

showed that the rate of the growth of bacteria increased with the increase in the incubation period, the

2. Introduction: Each student was given unknown bacteria and was instructed to perform a variety of experimental tests that would help to identify their bacteria. During the process of identification, the unknown bacteria was added to many different testing medias using aseptic technique. They are as follows: lactose fermentation on eosin methylene blue (EMB), TSI (Triple Sugar Iron agar), Phenol red sucrose, the SIM test, H2S by SIM, IMViC (indole, motility, voges-proskauer, and citrate), Urease (urea broth), PDase (Phenylalanine Deaminase), Lysine Decarboxylase, and Ornithine Decarboxylase. Colonial morphology on EMB was used to

Each mixed culture that was tested had one gram positive and one gram negative bacterial species. The possible species of bacteria that could have been isolated from the mixtures included the following: Bacillus subtilis, Corynebacterium glutamicum, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Enterobacter aerogenes, Salmonella enterica, and Pseudomonas aeruginosa. The identities of the unknown species were determined through comparing the experimental data against data acquired from earlier experimentation.

The purpose of the two experiments was to determine the fundamental effects that temperature has on the growth and survival of bacteria. During the first experiment five different bacterial broth cultures of Escherichia coli, Pseudomonas fluorescens, Enterococcus faecalis, Bacillus subtilis and Bacillus stearothermophilus were individually incubated at temperatures of 5, 25, 37, 45 and 55°C for one week in an aim to distinguish the effect temperature has on growth and survival of the five different species. After one week they were observed for distinguishable changes by the turbidity showing an indication of bacterial growth, or the clarity an indication of no survival.